Portable traffic sign and base therefor

Abstract

A traffic sign construction adapted to be selectively placed on top of a rigid base during certain periods, such as during school hours, periods when parking or turning is restricted, etc. The rigid base may be shaped like a conventional cast iron lane marker, having a convex top and a round bottom, and it is adapted to be permanently mounted along (or within) the boundaries of a vehicle roadway. A generally vertical bore in the center of the base extends to the top, so that a sturdy shank which has already been secured to the bottom of the traffic sign may be selectively inserted and removed from the bore without the requirement for any tools or special skill. A spring-loaded ball is preferably provided in either the bore or the shank, and a complementary recess is provided in the other of the two, so that they will be held together when they are subjected to only moderate loads--such as wind loads. When a person jerks the sign vertically upward, the spring-loaded ball will allow the sign to be separated from the base. Provision is made for washing out the interior of the base if it should happen to become fouled, by including openings at ground level which communicate with the vertical bore through appropriate passages. The ground-level openings (and passages leading thereto) are at least as large as the bore diameter, so that anything that can be put in the top of the base can be removed from the bottom. Also, no rain water is trapped in the base when the sign has been removed, because the ground-level openings preclude such trapping. No parts of the base are exposed to damage by vehicle wheels that might inadvertently pass over a base that has been permanently installed along a roadway. Preferably, the sign post is connected to the shank by an element which is relatively strong in tension but which will readily fail due to a significant shear load, such as when the sign is accidently struck by an errant automobile.

Description

This invention relates generally to temporary road markers, and in particular it relates to a marker in which an information-bearing sign is capable of being temporarily attached to a base, which base may be permanently affixed along or in a highway or the like.

There are many instances in which temporary highway markers, school zone signs, traffic control warnings, etc., have been devised for use on streets, parking lots, and highways, for the purpose of giving information to drivers. Exemplary of such devices are those disclosed in the patents to: Byrd U.S. Pat. No. 3,212,415; Fonda U.S. Pat. No. 2,167,564; Gubela U.S. Pat. No. 3,451,319; and Alexander U.S. Pat. No. 3,564,984. A common characteristic of these and many other traffic control signs is that they provide for the interlocking of co-operating parts in a base and an upright post. There is a pronounced difficulty with such locking schemes, however, if rain, snow, and dirt causes the recepticle in one part to become clogged or filled such that it will not accept a mating element of the other part. Thus, properly designed and manufactured interlocking parts can almost always be easily fitted together when they are new and clean. Too, after they are joined together on site, they usually are effective to lock out dirt, snow, sand, salt, trash and the like; but, if subsequently they are ever separated, they leave exposed certain grooves, cavities, ears, lugs, apertures, etc., which are capable of being filled and/or damaged by contact with vehicle wheels, etc. If it were desired that the base should be permanently left alongside a street and an information-bearing sign should be only temporarily affixed to the base, then devices of the past would not suffice. Exemplary cases where signs are only temporarily needed are: school zones, intersections where turns are restricted only during certain hours of particular days, construction or repair sites where work is carried on only during certain hours, loading zones for businesses, restricted parking area for parades, funerals or sports events, and unusual driving conditions such as ice on bridges, etc.

With particular attention to school-zone problems, it would be desirable to provide a warning sign which could be temporarily affixed by relatively young person, e.g., students who serve a safety patrol or the like. Such students cannot always be expected to possess a great deal of mechanical skill, nor should they be expected to expose themselves to prolonged danger from passing vehicles during the time they are installing or removing warning signs. Hence, it is an object of this invention to provide a temporarily installable warning sign which can be readily put in place and removed by the use of simple techniques.

It is another object of this invention to provide an information-bearing sign which can be readily affixed to a base which is permanently mounted within or alongside a vehicle roadway.

Still another object is to provide a mounting means for a sign post which includes a shear pin or the like, such that if a vehicle accidentally strikes the post, then the post can be yieldably separated from a fixed base, hopefully causing relatively litte damage to either the vehicle or the post.

An additional object is to teach a manner in which existing highway buttons or lane markers can be modified so that they can be utilized as bases for temporary warning signs.

One more object is to provide a temporary mounting for a portable warning sign which can be installed and removed without the need for any tools.

These and other objects and advantages will be apparent from the specification and the drawings provided herewith. In the drawing:

FIG. 1 is a perspective view of a combination lane marker/sign base of the invention, showing a portion of an upright post upon which a traffic sign may be mounted.

FIG. 2 is an cross-sectional, elevational view of a base shown in FIG. 1.

FIG. 3 is a fragmentary, elevational, cross-sectional view of a shank connected with a base.

FIG. 4 is a fragmentary, elevational view of a ground level opening on a base, which opening permits the vertical bore in the base to remain clear of debris and rain water, etc.

FIG. 5 is a cross-sectional view of another embodiment of the shank, showing the shear bolt which connects the shank and the bottom of a sign post.

FIG. 6 is a view of the structural element at the bottom of a sign post, taken in the plane VI--VI of FIG. 5. FIG. 7 is an elevational view of a base with two wedge-shaped leveling shims installed thereunder.

FIG. 8 is a top view of one of the wedge-shaped shims shown in FIG. 7.

FIG. 9 is a view similar to FIG. 3 which shows how a conventional lane marker may be modified to accept a shank of the invention, and

FIG. 10 is a diagramatic plan view of a road intersection.

According to this invention, a rigid base is adapted to rest on top of the ground along a boundary of a vehicle roadway. By the expression "boundary", it is intended to broadly encompass the sides of any traveled lane, whether that lane is a single lane within a multiple-lane highway, or the sides of a one-lane road, etc. Since the object of a warning sign is to convey information to the vehicle drivers, it is of course desirable that the base be as close to the vehicle's path of travel as is practical; the closer the sign is to his cone of front vision, the more nearly certain it is that a driver will see the displayed sign among all of the other regulating and advisory traffic signs and commercial advertisements, etc., which compete for his attention. Neither the base nor the sign should occupy any more space than is absolutely necessary, however, since it would thereby introduce its own hazard to traffic. Some temporary sign bases of the past were relatively heavy cast iron or concrete discs which were rolled into position when the signs were to be used. In order to have any stability in even a modest wind, such signs usually had heavy bases of 18 inches to 20 inches wide. When heavy enough to stay in place and do their job, they usually were awkward to move into position. Also, because of their weight, they could become particularly dangerous projectiles if they were ever struck by a vehicle with enough force to propel them through the air. Furthermore, such portable signs (with their permanently attached bases) were subject to being put in place from day to day with a varying orientation, e.g., sometimes they may have been perpendicular to approaching traffic, sometimes they were turned slightly to the right, and sometimes turned to the left. Hence, there was no reliable way that a traffic control engineer could proscribe an optimum orientation for prior portable signs and then realistically expect that his proscriptions would be followed by the various persons who would be setting the signs in place.

Another liability of previously used "portable" signs with bases up to 20 inches wide is their bulk with respect to the typical roadway. If such wide bases are rolled to the center of a residential street so that their signs may announce the proximity of a school or other activity deserving special attention, it can be seen that such bases will take from the available driving space an inordinate amount of space. It can be appreciated, therefore, why such temporary signs have not found favor with some police departments or traffic and safety organizations. In fact, as of 1973 there was no really adequate technique for mounting a regulatory school zone sign in the proximity of our nation's schools.

A widely accepted marker for establishing "safe zones" and indicating lanes of a vehicle roadway does exist, however; such markers are usually known as "buttons" or simply as "cast iron markers". They typically have a diameter up to 12 or 14 inches, and a height of about 3 1/2 inches; most older buttons are made of cast iron, while some newer ones are made of plastic or aluminum. Such markers or buttons are commercially available from national supply houses such as SA-SO, Inc, of Grand Prairie, Tex. Naturally, it is desirable that any such button or marker which is placed in a roadway should have as low a profile as possible, so that any vehicle which accidentally hits such a marker would not be immediately thrown out of control or suffer premature tire failure, etc. Too, if a vehicle somehow straddles a row of buttons, it is important that the buttons be low enough to provide adequate clearance between the vehicle's bottom structure and the top of the buttons. While the larger buttons have not been looked upon with favor by all traffic control engineers, most drivers have learned to be alert to their presence and avoid them. Hence, the adaptation of such markers or buttons as the requisite base for a warning sign described herein is reasonable.

A preferred dimension for the rigid base 20 of FIG. 1 is a diameter of approximately 71/2 inches and a height of approximately 31/2 inches. The base 20 may be made of any suitable material, such as cast iron, aluminum, or plastic, but cast iron is generally preferred because of its rigidity and strength. It will typically protrude above the roadway, and usually will be permanently affixed thereto. Since the diameter of the base 20 is relatively small (in order to minimize the consumed space and therefore maximize the travel way available for vehicles), the stability of the entire device will naturally be improved by the use of anchoring bolts, nails, glue or the like to secure the base to the roadway. The upper surface of the base 20 is preferably convex, as is conventional with other traffic buttons. The upper surface of the base 20 is provided with three widely spaced recesses 22 at radially disposed locations around the base. As can perhaps more advantageously be seen in FIG. 2, each of said recesses 22 has a horizontal ledge 24 with an aperture 26 through which a mounting bolt 28 may be inserted.

Also visible in FIg. 2 is a generally vertical bore 30 which extends to the top surface of the base 20 where it forms an opening 32 of given size and shape. The opening 32 is adapted to receive a structural element 34 (FIG. 3) which constitutes a part of a portable traffic sign.

Referring still to FIGS. 1 and 2, at least one opening 36 is provided near the bottom edge of the base 20, at ground level. The size of the opening 36 is such that it can accommodate (i.e., pass) any particle of matter which can pass through the top opening. Hence, if the opening 32 has a diameter of D, then the opening 36 should have a size appropriate for letting a marble or rock of diameter D pass therethrough, also. If two openings 36 are provided in a base 20, they are ideally located so that a stick or rod may be inserted into one of the openings and caused to protrude out of the other opening. By manipulating a rod through the two openings 36, any trash or soil that enters the opening 32 (and which is not removed by rain) can be eliminated from the hollow base 20, so that the bore 30 will remain clear and a shank 34 can be readily inserted therein. If a substantially solid base is employed rather than a hollow one (as shown in FIG. 2), then an appropriately sized passage would naturally be included between the top opening 32 and the ground-level openings 36 in order to insure that the base will be essentially self-cleaning. With regard to such a passage it is important that it be inclined downwardly so that it will not unduly trap rain water when the shank 34 is removed and the opening 32 is exposed; this is because such trapped water--if it froze--might expand enough to rupture a wall of the base. Of course, a short protective plug could be substituted for the shank when the sign is to be removed; but such a plug might be subject to accidental loss or theft Accordingly, vandals, etc. Accordinly, it is preferred to simply anticipate that rain will be present and to utilize it to wash foreign matter out of the interior of the base, rather than to try (perhaps ineffectually) to exclude it from the base.

Referring specifically to FIG. 3, a sign post 38 having at its bottom end the aforementioned shank 34 is shown in place in a base 20. A spring-loaded ball 40 holds the shank 34 securely in place against wind loads, but releases the shank when an upward thrust is imparted to the post 38. A satisfactory spring 42 is No. 151A manufactured by Associated Spring Corporation of Bristol, Conn., which is 25 gauge wire coiled to a 1/4 inch diameter. When the shank 34 has a 1 inch diameter, the spring 42 will typically have a 1/2 inch length, and it will normally be held in place by a set screw 44 or the like. A "safe load" for such a spring (in an axial direction) is 1.2 lbs., but it will readily resist a 10 lb. vertical pull on the shank 34. The hardened steel ball 40 is adapted to engage a recess or groove 46 in the bore 30, but the arrangement could be reversed such that a spring-loaded ball in the base would engage a recess in the shank. An alignment pin 48 is advantageously provided at the juncture of the post bottom and the base top, so that it may engage a recess 49, thereby insuring that the shank or probe 34 can only be inserted one way. This is especially useful when the bore 30 and shank 34 are cylindrical; but it can still be used to advantage even if the shank has a square cross-section.

In FIG. 5, a probe 34A is shown in cross section, with a shear element (bolt 50) illustrated as holding disk 52 and post 38 securely to the probe. A 3/8 inch steel bolt 50 in such a construction will securely hold a sign against substantially any anticipated wind load, e.g., up to about 100 m.p.h. It should be noted that the threads on the bolt 50 traverse the interface between the disk 52 and the shank 34A, so that shear failure of the bolt (if the sign should be accidentally struck by an automobile) will occur in a threaded portion of the bolt. In order to minimize the danger to surrounding objects after a sign has been accidentally sheared off, it is preferred that the sign be as light as possible; for this reason, a material like fiberglass is preferred for the upper structure of the sign.

Referring still to FIG. 5, it has been found to be extremely difficult to tighten a bolt 50 tight enough so that a person cannot simply twist the disk 52 counterclockwise and loosen the bolt; the mechanical leverage which is achieved through the relatively wide disk 52 is believed to explain this characteristic. To prevent the disk 52 from turning with respect to a shank 34A, it is desirable to have the alignment pin protrude above the top of the shank for a short distance, e.g., 1/16 inch. A shallow recess 54 is provided in the bottom surface of disk 52, to cooperate with pin 48 in preventing rotation of the disk about its center. The recess 54 is shaped to provide clearance for the pin 48 along a line through the bolt 50, so that shearing forces in the directions represented by arrow 56 will not be resisted by the pin 48. Shearing forces in the directions represented by the arrow 58 should not be unduly affected by the pin 48, so that bolt 50 will shear as planned when subjected to sufficient dynamic loading.

While the shear member 50 does provide "breakaway" protection (so that the sign does not have properties of an immovable object if it is ever struck by an automobile), it is sturdy enough to resist damage due to carelessness or inattention during those times when the sign is not installed in a base. Thus, if a person happened to drop a sign and the shank 34 struck its side on a hard surface, the 3/8 inch bolt would resist such modest shear loads. Similarly, the shank itself is preferably made of tool steel, e.g., E.M. Jorgenson Co. 12L-14 tool steel, so that it will normally resist most any abuse. The alignment pin 48 can be effectively made from drill rod, so that it is relatively immune to physical damage. The mounting plate 52 and the shoulder on shank 34 are preferably about 1/4 inch thick, so that they are very strong. Accordingly, the entire construction can be placed in the hands of even relatively young persons without apprehension that it might be quickly damaged. This attention to strength and durability is justified because one purpose of the invention is to provide a portable sign construction that can be employed by school-age children to mark a school crossing zone or the like. When the sign is not needed to warn motorists of a potential hazardous situation, it should be removed and placed in storage; and it is during the movement to and from storage that the durability of the construction is likely to be rather severely tested.

Referring next to FIG. 7, another example of a combination sign base/lane marker for a vehicle roadway is shown installed on a roadway which is not level. Since it is usually desired that a sign post 38 always be vertical, a means for leveling the lane marker is provided, including at least one--and preferably two--shims having a wedge-shaped configuration. As shown in FIG. 7, two washers or shims 70 are provided, and (in this figure) their thickest portions are adjacent one another so that the maximum tilting of the base 20 with respect to the roadway is accomplished. A plurality of apertures 72 are provided in each of the washers or shims 70, so that the two shims may be rotated with respect to one another and appropriate bolts 28 may be inserted therethrough to securely fix the base to the ground. It is preferred that the shims be continuous rather than like a washer (with a hole in the middle), so that foreign matter or rain will not be trapped inside a shim. As shown in FIG. 8, there are twelve apertures 72, and the shims may be rotated such that three bolts 28 (suggested in FIG. 7) may be placed through three sets of aligned holes when securing a base to the ground. A distinct advantage of using at least two shims 70 is that a post 38 may be readily erected so that it is essentially vertical, by merely changing the relative orientation of two shims.

While the base shown in FIGS. 1-3 has been specially designed to foster the temporary mounting of a warning sign thereabove, there may be certain circumstances which would make desirable the adaptation of existing lane markers for the same purpose. Since the basic purpose of a base as disclosed herein is to provide an anchor for the mounting of a temporary sign, it might be possible to satisfactorily modify a commercially available lane marker by adding thereto a special sleeve 80 which is adapted to fit within a large vertical recess created in the top of a base 20A. The wall thickness of commercially available cast iron buttons may pose somewhat of a problem, however, since it will not usually be as great as the thickness of a specialized button 20 disclosed herein. Accordingly, welding may be advantageously used in addition to threading as a means for securing a sleeve 80 to a button 20A. A sleeve 80 should be rust-resistant and have a recess or groove to accommodate a locking ball on a shank 34. The sleeve 80 should have a length approximately the same as the shank 34, e.g., 1.5 inches. Regardless of the latching means which is employed, however, it should be remembered that the sign-mounting construction is preferably simple enough to be engaged and disengaged by a relatively young person--and without the aid of any tools.

Because most buttons are intended to remain permanently affixed in a roadway even when signs are not affixed thereto, it is appropriate to pay attention to protecting all of the components and making them immune to damage from accidental impact with vehicle wheels. Of course, permanently mounted buttons with an upright sign mounted thereon will be more readily seen (and avoided) than will be the same button without a sign. However, recognizing that someday a driver may inadvertently steer his vehicle over one of the buttons, it is preferred that a round button have a diameter no greater than about 12 inches and a height less than 4 inches. It is also believed that a round button should have a diameter of at least six inches, in order to foster stability on windy days.

In use of the embodiments of the invention, the need for a portable traffic sign is first established by considerations relating to traffic safety. Such considerations will typically include the need to warn drivers of an unusual condition ahead, an intersection where turning is restricted during certain hours of the day, the proximity to a church where services are being conducted, an area where children may be passing to and from school, a funeral home where a service may be in progress, etc. All of the aforementioned situations make desirable the temporary mounting of a warning sign for drivers, followed preferably by the removal of the sign so that it does not remain at a site when its message is unnecessary. (Removing the sign precludes its damage from vandals, errant automobiles, etc.) The sign is normally removed by a policeman, construction worker, traffic controller, or safety patrol member, etc.; the removed sign would typically be placed in storage until it is again needed to convey its information to approaching drivers. In FIG. 10, there are several possible locations for the bases 20 to be mounted. The bases 20 may stand alone along the center line of a street, or they may be mounted on top of a curb; or they may be in series with conventional lane markers which are not adapted to have a sign mounted thereon, but are merely used for the purpose of segregating one lane of traffic from another.

Having determined where a portable sign can be advantageously used, the base 20 is then installed within or along the boundaries of the roadway; conventional bolts 28 would be inserted through the generally vertical peripheral recesses and driven into the roadway, as is customary with other lane markers. If the street is not level, a base can be made substantially level by inserting an appropriate number of shims 70 under it, as illustrated in FIG. 7. Too, if a base is to remain in one place for only a a few days (such as at a road repair site), a simple long spike inserted through a fairly central hole in a base may be more appropriate than a plurality of peripheral bolts 28 for holding a base in position. Once the base 20 is installed, it will probably need no further attention, and it can remain as a permanent fixture of the roadway. As with other lane markers, it may be painted periodically to protect its surface and improve its appearance, and a rod may occasionally be pushed through the base to dislodge any debris that may be caught. During dry weather, cleaning water may be poured into the generally vertical bore 30 to further clean it. If the base is made of malleable cast iron, it should last for many year, while the sign may be replaced as often as seems necessary. If the bore 30 should experience too much wear from frequent use, a steel sleeve or bushing may be affixed to the base 20 to insure a tight fit between the fixed base and a removable shank 34.

One further advantage of the system taught herein is that a qualified traffic engineer (or other professional) can decide exactly where and how a base should be installed, so that a sign which is later placed on top of the base will satisfy appropriate safety standards and codes. Once the base 20 and its alignment recess 49 are fixed on a roadway, any person may come along and correctly orient a sign on top of the base. The certaintly with which portable signs can be located with this invention should be recognized as being in marked contrast to the randomness with which prior portable signs, with their heavy concrete and steel bases, were set up by relatively unskilled persons. Too, this invention fosters the implementation of one of the most important facets of temporary regulatory and advisory signs, namely, that they be removed from view during those hours when they are not needed--so that drivers will not tend to become immune to their message.

Afer the base 20 is made ready, a person may simply carry a portable sign (with a suitable shank like that shown in FIG. 3 attached to the bottom) up to the base. By inserting the shank into the base 20 and aligning a key or pin 48 with its recess 49, the shank ill descend far enough until the spring-loaded ball engages the matching recess in the vertical wall of the bore 30. The matching ball and recess will prevent the shank 34 from "walking" out of the bore 30 due to any wind--induced vibration. Of course, other spring-biased elements besides a captive ball may be used to secure the two structures (the shank and the base) together. A rather close fit (e.g. 0.005 inch) between the shank and the vertical bore is preferred, so only a relatively light spring is needed to keep the shank secured within the base. If the sign post 38 should ever be struck by a car, the impact may be severe enough to shear the bolt 50, so that the post is no longer held rigidly to a base. The shank 34 will not be damaged by such an impact, and it may be later removed from the base and connected with a new bolt to the same sign post or a new one. Until the shank 34 is removed from the base, only its wide, flat shoulder 53 (typically 1/4 inch or less) would protrude above the base; hence it would constitute no threat to either persons or vehicles that might somehow come into contact with it. Indeed, it is the very low profile of the construction--after shear failure has occured--that contributes to one of the very pronounced advantages of the system, namely, that the bases can be mounted so very close to the traveled roadway.

While only the preferred emobodiments of the invention have been disclosed in great detail herein, it will be apparent to those skilled in the art that modifications thereof can be made without departing from the spirit of the invention. Thus, the specific structures shown herein are intended to be exemplary and are not meant to be limiting, except as described in the claims appended hereto. For example, the size and shape of a base may be altered as necessary to fit special requirements; similarly, the shape of a shank may be varied, as long as it can be easily inserted and removed as disclosed herein, etc. If the bore 30 were to be provided in a base at some angle so that it was not truly vertical when installed, naturally the inclination of the shank would be similarly modified so that it would still mate with the bore while leaving the sign post vertical. These and other modifications may be apparent to those skilled in the art, and are intended to be encompassed by the following claims.

Claims

What is claimed is:

1. an article of manufacture, comprising:

a. a rigid base adapted to rest permanently on top of the ground along a roadway, said base having an opening in its top leading to a generally vertical bore for receiving a structural element which forms a part of a temporary traffic sign, and the base further having at least one opening near its bottom edge which is connected through a passage with the vertical bore with the bottom opening and the passage having a size which is at least as large as the top opening, such that any trash or soil which may enter the top opening can pass through an unobstructed flow path through the base and out of the bottom opening;

b. an upright post having at its top a traffic sign and at its bottom an elongated shank, with the shank having a configuration such that it can be iserted in the vertical bore, and the nominal clearance between the shank and the vertical bore being about 0.005 inch; and

c. means for selectively holding the shank within the vertical bore of the base, said means comprising a spring-biased element on the shank or the base, and a recess for engaging the element on the other of the two structures, whereby the shank and its associated traffic sign may be selectively inserted and removed from the vertical bore in the base.

2. The article claimed in claim 1 and further including a shearing member extending axially upward from the shank into the upright post, said shearing member being mounted so as to hold the post securely to the shank when the member is in tension but to fail in shear upon the post being subjected to impact by a moving automobile.

3. The article as claimed in claim 1 wherein there is additionally provided a cooperating key and recess at the juncture of the post bottom and the base top, such that the shank can only be secured in the vertical bore with a single orientation in which the key is aligned with the recess.

4. The article as claimed in claim 1 wherein the base constitutes a rigid button or near hemispherical shape which is at least partially hollow, and the bottom opening lies just above ground level so that the base does not unduly trap rain water which may enter through the top opening when the shank is not mounted therein, whereby the base may be left permanently attached to the ground in the manner of conventional traffic lane markers.

5. A construction useful as a supporting foundation for temporary traffic information signs, comprising a rigid base adapted to be affixed to the ground along a roadway, the base having a relatively thick upper structure with a generally convex outer surface which protrudes above the ground, and said structure having a generally vertical bore which intersects said outer surface at a top opening of given diameter, and said bore having a substantial length for resisting the bending loads from wind blowing against a traffic sign mounted on the base, and said base having at least one ground-level opening at it periphery, with the size of each ground-level opening being such as to accommodate any particle which can pass through the top opening, with the top opening and each of the ground-level openings being connected by a passage such that nay liquid or solid matter is the nature of trash which enters the top opening can be physically removed through a bottom opening, whereby the base may be permanently affixed to the ground and left in place even when a traffic information sign is not coupled to the base so as to block the top opening against the entrance of foreign matter.

6. The construction recited in claim 5 and further including tapered shim means for installation between the ground and the base for causing the base to rest horizontally even though the ground is slanted, whereby the post of a traffic information sign can still be vertical even when it is attached to a base mounted on slanted ground, and said shim means further having a periphery which is the same size as the bottom of the base, and further having orientation-fixing means which permit the shim means to be oriented with respect to the base in more than one manner while still remaining evenly covered by the base.

7. The construction recited in claim 6 wherein the base has a round bottom and the tapered shim means comprises a pair of wedge-shaped discs which are rotatably adjustable with respect to each other, with the diameter of the discs being substantially the same as the diameter of the bottom of the base.

8. The construction as claimed in claim 5 wherein the base has a plurality of spaced peripheral bolt holes through whcih the base may be affixed to the ground, with the location and quantity of said bolt holes defining a certain hole pattern, and further including a tapered shim for installation between the base and the ground, with said shim having at least two sets of peripheral holes, each of which sets corresponds to the certain hole pattern on the base, whereby the inclination of the installed base is a function of which set of shim holes is aligned with the base holes.

9. The construction as claimed in claim 5 wherein the generally vertical bore in the base is appreciably larger than the shank of a traffic information sign which is to be mounted thereabove, and wherein a rigid sleeve is affixed within the vertical bore so as to receive the shank and to transfer bending loads from the shank to the base, and further including spring-biased means for resisting disenagement of a shank once it is installed over a base.

10. A temporary traffic control apparatus, comprising:

a. a rigid base adapted to be permanently affixed within the boundaries of a vehicle roadway, with the base protruding above the roadway, and having a generally vertical and non-threaded bore extending to the top of the base, such that a rigid and elongated probe may be inserted into and tightly fitted within the bore, and the base having a generally round bottom with a diameter of at least 6 inches but no more than about 12 inches, and the top of the base being generally convex, whereby the base is relatively immune to damage by contact with vehicle wheels; and

b. a post selectively secured on top of the base, such that an information-bearing sign which is attached to the post may be observed by vehicle drivers, with said post having firmly fastened to it bottom an elongated probe with a configuration exactly matching that of the vertical bore, and the post being fastened to the probe with a shear element which is adapted to yield in the event of accidental impact of a vehicle with the post, which inpact may occur from any horizontal direction with respect to the longitudinal axis of the post, whereby a post which is accidentally struck can be severed from its connection with the rigid base so as to leave no part of the apparatus protruding appreciably above the base.

11. The apparatus as claimed in claim 10 wherein the rigid base is made of malleable cast iron having a diameter of aboub 7 1/2 inches and a height of about 3 1/2 inches.

12. The apparatus as claimed in claim 10 and further including a spring-biased means for holding the probe in engagement with the base until such time as the probe is subjected to a substantial vertical upward load, whereby the sign post may be successively engaged with and removed from the base by over-riding the biasing force of said spring-biased means.

13. In a construction adapted for marking lanes in a roadway, including a near-hemispherical metal button having a diameter of about six inches, and said button having means by which it may be secured to a hard-surface roadway, the improvement comprising:

a generally vertical bore in the button extending to the top thereof where it forms a circular opening having a diameter of about one inch, with said top opening being adapted to receive a cylindrical shank having a diameter of about one inch, with the cylindrical shank constituting the bottom portion of a traffic sign that is to be temporarily mounted over the button, and the button having means for securely holding the cylindrical shank against vibration when it is inserted into the bore, and the button further having means for restricting the cylindrical shank to a particular radial orientation with respect to the button, whereby a traffic sign may be repeatedly connected to and removed from the button, and each time the sign is connected to the button it will have the same orientation.

14. The combination as claimed in claim 13 and further including at least two ground-level openings, each of which has a size which is adequate to pass any object which can be inserted into the top opening, and the top opening being connected with the ground-level openings through passages such that any debris which enters the top opening can be expelled from a ground-level opening.

15. An article of manufacture, comprising:

a. a cast iron base of near hemispherical shape adapted to rest permanently on top of the ground along a roadway, said base having a round opening in its top leading to a generally vertical bore for receiving a cylindrical shank which forms a part of a temporary traffic sign, and a base further having at least one arched opening near its bottom edge which is connected through a passage with the vertical bore, with the bottom opening and the passage having a size which is at least as large as the top opening, such that any trash or soil which may enter the top opening can pass through an unobstructed flow path through the base and out of the bottom opening;

b. an upright post having at its top a traffic condition indicator and at its bottom a cylindrical shank, with the shank having a length at least as long as the vertical bore, and the nominal clearance between the shank and the vertical bore being about 0.005 inch, and the bottom of the shank being rounded to facilitate its entrance into the bore;

c. means for selectively holding the shank within the vertical bore of the base, said means comprising a spring-biased ball within a passage on the shank, and a recess for engaging the ball in the vertical bore, whereby the shank and its associated traffic sign may be selectively inserted and removed from the vertical bore in the base;

d. a shearing member in the form of a bolt extending axially upward from the shank into the upright post, said shearing member being mounted so as to hold the post securely to the shank when the member is in tension; and

e. an alignment key mounted adjacent the shank and cooperating recess on the base at the juncture of the post bottom and the base top, such that the shank can only be secured in the vertical bore with a single orientation in which the key is aligned with the recess.